wooooo hoooo!!! First to vote for 10s lol. I like the sound of them better and for me I have more control playing. Anything lower than 10s seems to be way too loose, plus with 10s your fingers get stronger and you can play faster more effortlessly .
On my Ibanez and my Strat I used 9's, but since I got a Les Paul, I haven't played the others since, and I've converted to 10's. The shorter scale length makes the 10's almost feel like 9's.
I always have used 10's, but just refinished an old Guild Jet Star and put a bigsby on it. I decided to try Power Slinky's which are 11's. I like them so far and think I might try them on some of my other guitars.
I used 9s for ages, then switched to 8s, which I found just to be too rubber bandy. Then went back to 9s, then up to 10s on my Jackson and 10-52 on my E$P (which I owned for 2 weeks).
Since i've got a new EBMM JP i've gone back to 9s, and enjoying it.
Was on 9s for ages but moved up to 11s and doubt I'll ever go any lower. 11s for standard tuning, 12s for half-step down, 13s for D-D, etc. Always gotta have a 54 on the bottom though